Conditionally return

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class TestReturnValues {
    public static void main(String[] args) {
        for (int i = 1; i <= 5; i ++) {
            List<Integer> randomList = new ArrayList<>();
            Random rd = new Random();
            for (int j = 1; j <= 5; j++) {
                randomList.add(rd.nextInt(8) - 1);
            }
            Object result = allPositiveFigures(randomList);
            if (result instanceof Boolean) {
                System.out.println("All figures are no less than zero.");
            } else if (result instanceof List) {
                System.out.println("Some figures are not positive.");;
            } else {
                System.out.println("Unknown return type found!!!");
            }
            System.out.println("----------------------------------");
        }
    }
    private static Object allPositiveFigures(List<Integer> list) {
        System.out.println(list);
        List<Integer> negativeFigures = new ArrayList<>();
        boolean flag = true;
        for (int i : list) {
            if (i < 0) {
                flag = false;
                negativeFigures.add(i);
            }
        }
        if (flag) {
            return true;
        } else {
            return negativeFigures;
        }
    }
}

[2, 5, 5, 4, 6]
All figures are no less than zero.
----------------------------------
[3, 3, 6, 0, 4]
All figures are no less than zero.
----------------------------------
[6, 4, 1, 3, 1]
All figures are no less than zero.
----------------------------------
[4, 3, 3, 1, 3]
All figures are no less than zero.
----------------------------------
[3, -1, 5, 5, 5]
Some figures are not positive.
----------------------------------

Process finished with exit code 0